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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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B727-200 maintaining FL350 autoplt and omega connected to the aircraft. Captain and first officer checking operations manual reference minimum fuel. Autoplt disconnected, no aural warning installed. Flight crew did not notice red warning light. Aircraft climbed to FL356, first officer noticed red light blinking and returned the aircraft to FL350. No comment from center.
| Attributes | |
| ACN | 347500 |
| Time | |
| Date | 199609 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : bff |
| State Reference | NE |
| Altitude | msl bound lower : 35000 msl bound upper : 35600 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdv |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 130 flight time total : 11000 flight time type : 8000 |
| ASRS Report | 347500 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 220 flight time total : 10000 flight time type : 2600 |
| ASRS Report | 347708 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
It was my leg and we were cruising at FL350, using omega and autoplt. I was checking book for minimum fuel considerations at slc due fuel overburn at scotts bluff. The first officer looked up to see autoplt disengaged light flashing and aircraft climbing through FL356. He took the controls and descended the aircraft to FL350. No other aircraft in vicinity. Neither one of us heard the autoplt click off nor did we hear the altitude hold switch click off. This was very unusual as these clicks are very noticeable and are the auditory signal since the sperry block iv autoplt has no auditory warning. Company uses 2 autoplts -- one has auditory signal, one does not. This creates a built in danger. Even a momentary distraction can crate a dangerous situation. An auditory signal on all autoplt disconnects should be mandatory.
Original NASA ASRS Text
Title: B727-200 MAINTAINING FL350 AUTOPLT AND OMEGA CONNECTED TO THE ACFT. CAPT AND FO CHKING OPS MANUAL REF MINIMUM FUEL. AUTOPLT DISCONNECTED, NO AURAL WARNING INSTALLED. FLC DID NOT NOTICE RED WARNING LIGHT. ACFT CLBED TO FL356, FO NOTICED RED LIGHT BLINKING AND RETURNED THE ACFT TO FL350. NO COMMENT FROM CTR.
Narrative: IT WAS MY LEG AND WE WERE CRUISING AT FL350, USING OMEGA AND AUTOPLT. I WAS CHKING BOOK FOR MINIMUM FUEL CONSIDERATIONS AT SLC DUE FUEL OVERBURN AT SCOTTS BLUFF. THE FO LOOKED UP TO SEE AUTOPLT DISENGAGED LIGHT FLASHING AND ACFT CLBING THROUGH FL356. HE TOOK THE CTLS AND DSNDED THE ACFT TO FL350. NO OTHER ACFT IN VICINITY. NEITHER ONE OF US HEARD THE AUTOPLT CLICK OFF NOR DID WE HEAR THE ALT HOLD SWITCH CLICK OFF. THIS WAS VERY UNUSUAL AS THESE CLICKS ARE VERY NOTICEABLE AND ARE THE AUDITORY SIGNAL SINCE THE SPERRY BLOCK IV AUTOPLT HAS NO AUDITORY WARNING. COMPANY USES 2 AUTOPLTS -- ONE HAS AUDITORY SIGNAL, ONE DOES NOT. THIS CREATES A BUILT IN DANGER. EVEN A MOMENTARY DISTR CAN CRATE A DANGEROUS SIT. AN AUDITORY SIGNAL ON ALL AUTOPLT DISCONNECTS SHOULD BE MANDATORY.
Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.